JPH0524863Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The metal cylinder head gasket according to this invention is sandwiched between the lower surface of the cylinder head and the upper surface of the cylinder block of an internal combustion engine to ensure airtightness and liquidtightness between both surfaces. Used to hold.

(Prior art) A cylinder head gasket is sandwiched between the lower surface of the cylinder head and the upper surface of the cylinder block of an internal combustion engine, and the high pressure combustion gas generated within the cylinder or between the cylinder block and the cylinder head is This prevents circulating cooling water and lubricating oil from leaking to the outside.

FIG. 2 shows an example of such a cylinder head gasket 1. This cylinder head gasket 1 has circular bore holes 2, 2 that match the opening shape of the top of the cylinder, small circular holes 3, 3 through which bolts for fixing the cylinder head to the cylinder block are inserted, and cooling water and lubricating holes. Through holes 4, 4 for passing oil
is drilled. Reference numeral 5 designates a grommet made of a thin metal plate attached to the inner peripheral edge of each bore hole 2,2.

Conventionally, such a cylinder head gasket 1 has a core material such as an iron plate with a hook or a wire mesh, and
They were made by imprinting compounds whose main ingredients were asbestos or carbon, or by pasting sheets of these materials. However, in recent years, with the spread of turbochargers, etc., there has been a strong tendency for the thermal load on engines to become high, and metal cylinder head gaskets with good heat resistance are increasingly being used.
A metal cylinder head gasket is made by stacking multiple thin metal plates such as galvanized steel plates or stainless steel plates with bore holes 2, etc. punched out.
It is constructed by attaching a grommet 5 to the inner peripheral edge of the.

FIG. 3 shows an example of such a conventional metal cylinder head gasket. The metal cylinder head gasket illustrated in FIG.
It is constructed by laminating one first metal thin plate 6 and two second metal thin plates 7, 7 in a sandwich pattern. Among them, two second metal thin plates 7,
Layers of sealing material 8, 8 such as nitrile butadiene rubber (NBR) or silicone rubber are formed on both the front and back surfaces of 7 by baking or other means.

Each of the second thin metal plates 7, 7 has a bore hole 2 and a cylinder head 11 connected to the cylinder block 10.
A small circular hole through which a bolt is inserted for fixing the engine, and a through hole 4 through which cooling water and lubricating oil pass are formed. Further, the first thin metal plate 6 has a bore hole 2, a small circular hole, and a through hole 4, like the second thin metal plates 7, 7.
is installed. Furthermore, a grommet 5 made of a thin metal plate is provided at the peripheral edge of the bore hole 2 formed in the first thin metal plate 6.

Annular protrusions 9, 9 are provided around the bore hole 2 and the through hole 4 through which the liquid passes, which are bored in the first thin metal plate 6, so that the pressing force around the hole 2, 4 is reduced. I'm trying to get higher.

Further, among the through holes 4 for passing liquid formed in both the first and second thin metal plates 6 and 7, the size of at least some of the through holes 4 is determined by the size of the upper surface of the cylinder block 10 and the cylinder head. The metal cylinder head gasket is formed smaller than the water holes 12, 12 opened on the lower surface of the cylinder block 1.
When the cylinder block 10 is held between the upper surface of the cylinder block 10 and the lower surface of the cylinder head 11, the flow rate of the cooling water sent out from the water hole 12 of the cylinder block 10 is restricted by the through hole 4.

That is, the openings of the water holes 12, 12 formed in the cylinder block 10 and cylinder head 11 are
Due to the necessity of forming these water holes 12 during casting, the opening area may be larger than originally required. Therefore, the size of the through hole 4 that matches the opening of the water holes 12, 12 is determined based on the size of the water hole 1.
The openings are made smaller than openings 2 and 12 to adjust the flow rate of cooling water to an appropriate value.

(Problems to be Solved by the Invention) However, the conventional metal cylinder head gasket constructed as described above has the following disadvantages.

That is, as a means for adjusting the flow rate of the cooling water in the through holes 4 for passing the cooling water, holes are formed in both the first and second thin metal plates 6 and 7 that constitute the metal cylinder head gasket, as described above. The through hole 4 provided in the upper surface of the cylinder block 10 and the cylinder head 11
As a result, the flow of cooling water collides with the surface of the second thin metal plates 7, 7, and this collision Therefore, the second thin metal plate 7,
It is unavoidable that parts of the sealing materials 8, 8 formed on both the front and back surfaces of 7 will peel off.

In particular, water vapor present in the cooling water that becomes hot during engine operation permeates through the sealing materials 8, 8 and the second thin metal plates 7, 7.
This will cause the sealing materials 8, 8 to rise and promote peeling of the sealing materials 8, 8.

That is, the nitrile butadiene rubber and silicone rubber used as the sealing materials 8 and 8 do not have perfect gas barrier properties (gas impermeability), so they allow water vapor contained in high-temperature cooling water to pass through, albeit in a small amount. It ends up. If the water vapor that has entered the interface between the sealing materials 8, 8 and the second thin metal plates 7, 7 remains as a gas, the amount of water vapor that enters the interface and the amount of water vapor that exits from the interface are In balance, no particular problem arises, but when the water vapor present at the boundary surface condenses into water droplets as the engine stops operating, these water droplets lift the sealing materials 8, 8. When the sealing materials 8, 8 rise, the peeling of the sealing materials 8, 8 progresses from this portion.

If a part of the sealing material 8 is peeled off in this way and the pieces of the peeled off sealing material 8 are mixed into the cooling water,
This may cause the pump that sends this cooling water to malfunction.

The present invention eliminates the above-mentioned disadvantages and provides a metal cylinder head gasket that does not cause the sealing material to peel off and cause pump failure.

(Means for solving the problem) The metal cylinder head gasket in this invention is
Similar to the conventional metal cylinder head gasket described above, the first through hole is formed at a position that aligns with the water hole opening on the bottom surface of the cylinder head and the top surface of the cylinder block, and a sealant is applied to both the front and back surfaces. A layer of sealing material is formed on both the front and back surfaces of the first thin metal plate with no layer formed thereon, and a second through hole is formed at a position aligned with the water hole, and the first thin metal plate is placed in a sandwich It is composed of two second thin metal plates sandwiched in a shape.

Bore holes are formed in the first and second thin metal plates at positions that align with each other.

Furthermore, in the metal cylinder head gasket of the present invention, the size of the first through hole is made smaller than the water hole, and the entire first through hole is located inside the water hole. , and the size of the second through hole is set to be equal to or larger than the water hole, so that the peripheral edge of the second through hole does not protrude inside the water hole.

(Function) The function of the metal cylinder head gasket of the present invention constructed as described above is similar to that of the conventional metal cylinder head gasket, but in the metal cylinder head gasket of the present invention,
The size of the second through hole formed in the second thin metal plate, which has a layer of sealant on both the front and back surfaces, is equal to or larger than the water hole opened on the lower surface of the cylinder head and the upper surface of the cylinder block. Because the peripheral edge of the second through hole does not protrude inside the water hole, the flow of cooling water sent out from the water hole opened on the top surface of the cylinder block collides with the surrounding area of the second through hole. There's nothing left to do.

In addition, water vapor present in the cooling water hardly ever enters the interface between each sealing material and the second thin metal plate. Moreover, each sealing material is strongly sandwiched between the front and back surfaces of the second thin metal plate, the lower surface of the cylinder head, the upper surface of the cylinder block, and the front and back surfaces of the first thin metal plate. Even if water vapor enters the interface and condenses on the interface, the sealing material will not float up.

As a result, the sealing material covering the area around the second through hole will not peel off, and fragments of the peeled off sealing material will no longer enter the pump for delivering cooling water and cause this pump to malfunction. .

The flow rate of the cooling water is controlled by the first through hole formed in the first thin metal plate without a layer of sealant on the front and back surfaces.
adjusted.

(Example) Next, the metal cylinder head gasket of the present invention will be explained in more detail while explaining the illustrated embodiment.

FIG. 1 is an enlarged cross-sectional view taken along the line A--A in FIG. 2, showing an embodiment of the metal cylinder head gasket of the present invention.

The metal cylinder head gasket of the present invention is composed of a first thin metal plate 6 and two second thin metal plates 7, 7 sandwiching the first thin metal plate 6 in a sandwich-like manner.

Among these, the first thin metal plate 6 is a thin metal plate such as a galvanized steel plate or a stainless steel plate, and has a first thin metal plate 6 that can be aligned with the water holes 12, 12 opened on the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10. A through hole 4a is formed therein. A layer of sealing material is not formed on either the front or back surface of the first thin metal plate 6, as in the case of the second thin metal plates 7, 7 described below.

Further, the two second thin metal plates 7, 7 are each formed by forming a layer of sealing material 8, 8 on both the front and back surfaces of a thin metal plate such as a galvanized steel plate or a stainless steel plate by means such as baking. I am using it. and,
These two second thin metal plates 7, 7 are also formed with second through holes 4a, 4b which can be aligned with the water holes 12, 12 which open on the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10. ing.

Bore holes 2 are provided in both the first and second thin metal plates 6 and 7 at positions that align with the cylinder holes 13. Also, although not shown, each thin metal plate 6, 7
A small circular hole is formed in the hole for bolt insertion.

Furthermore, in the metal cylinder head gasket of the present invention, the size of the first through hole 4a formed in the first thin metal plate 6 is adjusted to the size that opens on the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10. The first through hole 4a is made smaller than the water holes 12, 12, and the entire first through hole 4a is located inside the water holes 12, 12. and the second metal thin plate 7,
The size of the second through holes 4b, 4b formed in 7 is,
The peripheral edges of the second through holes 4b, 4b are made to be equal to or higher than the water holes 12, 12 so as not to protrude inside the water holes 12, 12.

Both the first and second thin metal plates 6 and 7 as described above.
has a first thin metal plate 6 in the middle, and second thin metal plates 7, 7 on both sides of the first thin metal plate 6.
The metal cylinder head gasket of the present invention is obtained by stacking the thin metal plates 6 and 7 in a sandwich pattern so that the holes 2 and 4 formed in the thin metal plates 6 and 7 align with each other.

Furthermore, in the embodiment shown in FIG.
Annular protrusions 9, 9 are formed around a, and when the metal cylinder head gasket is held between the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10, the portion where the protrusions 9, 9 are formed By increasing the pressing force, better sealing performance can be obtained. However, when the metal cylinder head gasket is used, each protrusion 9, 9 is completely crushed between the upper surface of the cylinder block 10 and the lower surface of the cylinder head 11, and the second thin metal plate 7, Seal materials 8, 8 provided on the front and back surfaces of 7
is strongly held between the front and back surfaces of the second thin metal plates 7, 7, the lower surface of the cylinder head 11, the upper surface of the cylinder block 10, and the front and back surfaces of the first thin metal plate 6.

In addition, a grommet 5 made of a thin metal plate is attached to the periphery of the bore hole 2, and the pressing force of the grommet 5 attachment portion is increased, so that the airtightness around the bore hole 2 can be better maintained. There is.

The metal cylinder head gasket of the present invention constructed as described above is used by being firmly clamped between the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10, like conventional metal cylinder head gaskets. Further, its function itself is similar to that of a conventional metal cylinder head gasket.

That is, by strongly holding the metal cylinder head gasket of the present invention between the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10, the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10 are exposed to the metal cylinder head gas. Layers of sealing materials 8, 8 and grommets 5 formed on the front and back surfaces of the second thin metal plates 7, 7 forming the front and back surfaces of the butt.
in close contact with the surface of

As a result, high-pressure combustion gas generated within the cylinder hole 13 opened on the top surface of the cylinder block 10 and cooling water flowing through the water holes 12, 12 can be prevented from leaking to the outside.

Also, so-called interlayer leakage, in which fluid leaks between the respective thin metal plates 6 and 7, is effectively prevented by the layers of sealing materials 8 and 8 that are present between the respective thin metal plates 6 and 7.

Furthermore, in the metal cylinder head gasket of the present invention, the sizes of the through holes 4b, 4b formed in the second thin metal plates 7, 7 are set such that they are opened on the lower surface of the cylinder head 11 and the upper surface of the cylinder block 10. Since the water holes 12, 12 are equal to or larger than the water holes 12, the sealing materials 8, 8 coated on the front and back surfaces of the second thin metal plates 7, 7 are exposed to the flow of cooling water.

In addition, water vapor present in the cooling water flowing through the water holes 12 is hardly allowed to enter the interface between the sealing materials 8, 8 and the front and back surfaces of the second thin metal plates 7, 7. That is, each sealing material 8, 8 and cooling water are as follows.
Extremely thin (for example, about 20 to 50 μm) sealing material 8,
Since only the inner peripheral edge of 8 comes into contact with the cooling water,
The amount of water vapor that passes through the sealing materials 8, 8 and enters the interface is so small as to be almost negligible.

Moreover, each sealing material 8, 8 is applied to the front and back surfaces of the second thin metal plates 7, 7, the lower surface of the cylinder head 11,
Upper surface of cylinder block 10, first thin metal plate 6
Since the sealing materials 8, 8 are strongly sandwiched between the front and back surfaces, even if water vapor enters the boundary surface and condenses there, the sealing materials 8, 8 will not lift up.

As a result, the sealing materials 8, 8 formed on the front and back surfaces of the second thin metal plates 7, 7 peel off, and the pieces enter the pump for feeding cooling water, which may cause the pump to malfunction. disappears. The flow rate of the cooling water is adjusted by a first through hole 4a formed in the first thin metal plate 6, which has no sealing material layer formed on either the front or back surface.

(Effects of the invention) Since the metal cylinder head gasket of the present invention is constructed and operates as described above, it has the same airtightness and liquidtightness as conventional metal cylinder head gaskets, and also has the same properties as conventional metal cylinder head gaskets. This eliminates accidents such as the sealing material attached to the thin metal plate peeling off and its fragments entering the pump and causing the pump to malfunction, which has a great effect on stable engine operation.

[Brief explanation of the drawing]

FIG. 1 is a view corresponding to an enlarged cross section taken along the line A-A in FIG. 2, showing an embodiment of the metal cylinder head gasket of the present invention; FIG. 2 is a plan view showing an example of a conventional cylinder head gasket; FIG. 3 is a view similar to FIG. 1, showing an example of a conventional metal cylinder head gasket. 1... Cylinder head gasket, 2... Bore hole, 3... Small circular hole, 4... Through hole, 4a... First through hole, 4b... Second through hole, 5... Grommet,
6...First metal thin plate, 7...Second metal thin plate,
8...Sealing material, 9...Protrusion, 10...Cylinder block, 11...Cylinder head, 12...Water hole, 13...Cylinder hole.

Claims (1)

[Scope of utility model registration request] a first thin metal plate having a first through hole formed at a position aligned with the water hole opening on the lower surface of the cylinder head and the upper surface of the cylinder block, and having no sealing material layer formed on either the front or back surface; A layer of sealing material is formed on both the front and back surfaces, and a second through hole is formed at a position aligned with the water hole, and two second thin metal plates sandwich the first thin metal plate in a sandwich-like manner. Bore holes are formed at mutually aligned positions in both the first and second thin metal plates, and the size of the first through hole is made smaller than the water hole, so that the entire first through hole is formed. is located inside the water hole, and the size of the second through hole is equal to or larger than the water hole, so that the peripheral edge of the second through hole does not protrude inside the water hole. Metal cylinder head gasket.